Large sandstone boulders for the construction of cromlech were dug from the vast forest area nearby.
Stonehenge, a megalithic structure in the south of England, is an eternal mystery for historians and archaeologists. How was it built? What functions did you perform? Where did the boulders that Stonehenge is made of come from?
Perhaps a new study published in Science Advances will still provide a definitive answer to this question. Most of the giant sarsen sandstone boulders appear to have a common origin and were mined in the West Woods area, about 25 kilometers from where Stonehenge itself was built.
This discovery supports the theory that the stones were brought to the construction site of cromlech (structures of vertically set boulders forming concentric circles) around 2500 BC, during the second stage of construction, and maybe a sign that its builders were from a highly organized society. This also contradicts the assumption that one of the boulders, the so-called Heel Stone, was mined in the immediate vicinity of the cromlech and installed earlier than the others.
To carry out their research, scientists had to develop a special technique for studying blocks, which reach nine meters in height and can weigh up to 30 tons. First, they analyzed the chemical composition of the rock using X-rays. “Most of the rocks share a common chemical composition, which allowed us to determine that we are looking for one main [mining] location here,” says lead author David Nash.
They then examined two core samples (material samples) obtained from one stone during restoration work in 1958. A more sophisticated analysis scheme using mass spectrometry was applied to these samples, which made it possible to detect a wider range of elements with high accuracy.
The analysis data were compared with the results of studying rocks from 20 possible mining locations. The closest in composition to the Stonehenge stones were sedimentary rocks in the West Woods forest massif. Previous studies of cromlech revealed that a number of relatively small boulders (called blue stones, bluestones) of Stonehenge were brought from Wales, from a quarry located 200 kilometers west of the structure. The new work shows that both the small stones and the sarsen blocks were brought in and installed at about the same time.
How the ancient inhabitants of Foggy Albion transported boulders weighing up to 30 tons over a distance of about 25 kilometers, scientists cannot yet explain. One of the more likely hypotheses is that the builders of Stonehenge used some kind of wooden sled. The significance of the site also remains mysterious.
In the future, the researchers want to determine as accurately as possible which route was used to transport the boulders. This can be found out by individual rock crumbs, which they hope to find in the vicinity of a cromlech.